Overall the trip was amazing.
I am so thankful there were a few extremely awesome people on that trip I wouldn't have met without Contiki.
Some of the add ons, like the Farmer's Dinner in Salzburg and the walking tours were gold. Some like the sort Gondola ride in Venice were not so enchanting. I skipped the Bunker tour in Prague, but the reviews from the people who did go were lackluster.
Contiki is great with selecting walking guides; Izzy and Kyle in Berlin knew their city and were passionate about it's history.
Kiara, the tour guide, was very, very good. Firo, the driver, was an A+ driver and very funny. Because we were on a modular tour (me and others didn't know that until Contiki emailed us days before leaving for the tour), we met everyone near the end of their traveling who the tour guide and the driver had a better report with them. But you can hardly blame anyone for having better relationships with each other because they've known them longer.
My main complaint are the beds in many of these hostels we stayed at. Yes they are hostels, and I had absolutely no problem sharing a room with multiple girls. But some beds had springs popping out for God sake! I know they're not meant to be the highest quality, but that's going a little too far. :/
Also, I would've wished to receive more knowledge of how to get places using public transport in different cities. They kind of scratched the surface of how we could navigate via metro, buses, etc. and gave us confusing maps before we arrived, but many of us still got lost. Definitely good stories to go home with, but it still means wasting time and paying more money to get back on track to our destinations.
I am planning to go with Contiki hopefully next year, so I highly recommend it still!